Packages for sterile medical devices, such as surgical sutures, are well known in the art. Processes for packaging sterile medical devices are similarly well known.
Surgical sutures are typically packaged in primary packages that prevent the sutures from being damaged during routine shipping, handling and storage. The primary packages containing the sutures are then packaged in conventional secondary packages that function as sterile barriers to maintain the sterility of the medical devices. These secondary packages are well known in the packaging arts. The type and structure of the secondary package utilized will depend upon a number of factors, including the type of medical device, the size and construction of the primary package, and the sterilization process utilized. There are a variety types of conventional sterilization processes which can be used for medical devices, including ethylene oxide gas, radiation, plasma and autoclaving.
Depending upon the type of medical device that is to be sterilized, one or more of these sterilization techniques may be utilized. For example, a medical device such as a suture made from an absorbable polymer may be sterilized in an ethylene oxide sterilization process, but may not be suitable for processing in a radiation sterilization process or an autoclaving process. The reason for this is that radiation or extreme heat may degrade the polymeric structure of the device, rendering it unusable during surgery or unsuitable for implantation into the patient's body. On the other hand, autoclaving or radiation may be more appropriate for a medical device made from a ceramic, a non-absorbable polymer, or a metal. In general, the choice of the type of secondary package will depend upon both the material of construction of the medical device and the type of sterilization process utilized.
In ethylene oxide gas sterilization, it is necessary to expose the medical device to both humidity and ethylene oxide gas for the process to work effectively. A conventional secondary package that is selected for a medical device subjected to an ethylene oxide gas sterilization process is known as a pouch or an envelope. Such pouches or envelopes typically consist of a sheet of a clear, gas impervious polymer film sealed about its periphery to a sheet of a gas pervious or gas penetrable polymer film such as TYVEK.RTM. spun-bonded polyethylene. The gas pervious film allows humidity and the sterilant gas to enter the pouch and thereby come into contact with the medical device (typically packaged within a primary package) contained within the sealed pouch. The gas pervious film also permits the sterilant gas and humidity to exit the pouch at the end of the sterilization cycle. After the sterilant gas is evacuated from the pouch, typically by the application of a vacuum, the interior of the pouch equilibrates with the ambient atmosphere via the gas pervious film.
For certain absorbable medical devices, prolonged exposure to ambient air, particularly humid air, during storage will cause the polymeric material to break down or degrade. It is often desirable to use ethylene oxide sterilization for such absorbable products since, as previously mentioned, radiation and autoclaving are unacceptable, but these absorbable products cannot be packaged in conventional gas sterilization pouches and stored and handled in a conventional manner.
In order to address this dilemma, special foil secondary packages have been developed for these devices. The foil packages when sealed provide a hermetically sealed enclosure that is substantially impervious to gases and moisture. The shelf life of the absorbable polymer device is extended since moisture infiltration into the hermetically sealed pouch is essentially eliminated. However, the use of ethylene gas sterilization processes with these types of foil pouches typically requires that the devices be sterilized with the pouch open on one end to allow the sterilant gas and humidity to access the interior of the pouch and contact the medical device. Different types of pouches and sterilization processes have been developed for these foil pouches. In one conventional process, the ends of the pouch are maintained in an open configuration during sterilization. After sterilization, the pouch is then maintained in an aseptic environment and aseptically sealed to provide for a hermetically sealed pouch having a sterile interior. Foil pouches or packages for absorbable sutures and a method of manufacturing the packages and packaging the sutures are disclosed in U.S. Pat. Nos. 5,623,810 and 5,709,067 which are incorporated by reference. A method of gas sterilizing absorbable sutures in open foil packages and then aseptically sealing the packages to produce hermetically sealed sterile enclosures is disclosed in U.S. Pat. No. 5,464,580 which is incorporated by reference. In other processes, the foil package may have a gas permeable header. After sterilization, the open end of the foil package is sealed adjacent to the header and the header is cut off. In another known process, the open foil pouch is sealed in a secondary package consisting of a conventional gas sterilization pouch. The open end of the foil pouch is sealed through the pouch after sterilization.
It is known that the aseptic sealing of sterile foil packages requires precise environmental controls and techniques including air filtering. These controls and techniques may be costly and difficult to implement and maintain. New foil packages and sterilization techniques have been developed which eliminate the need for aseptic sealing and processing. A multi-cavity secondary foil package having a gas permeable vent is disclosed in U.S. Pat. No. 5,868,244 which is incorporated by reference. In such a package, a medical device is loaded into each cavity. The vent is typically located interior to the periphery of the package, preferably centrally. This vented package is partially sealed prior to sterilization forming a gas tight peripheral seal and secondary seals such that the secondary seals form channels. The channels form a gaseous pathway between each medical device and the central vent. After sterilization, additional seals are provided to hermetically seal each individual cavity containing a medical device, thereby forming individually hermetically sealed secondary foil packages. The multiple package is then separated into individual hermetically sealed medical device packages and the vent is cut away as scrap. The use of this vented package eliminates the need for aseptic handling and processing.
The manufacturing of such foil packages having central vents requires that an additional step be performed which was not necessary in the prior art processes. That step is the mounting of the gas pervious vent to one of the two foil members, which make up the foil pouch. This vent must be carefully mounted so that there is no gas leakage about the periphery of the vent when it is mounted and sealed to an opening in foil member.
Accordingly, there is a need in this art for a novel manufacturing process for manufacturing foil packages for multiple medical devices having gas pervious vents.